Conventionally, a map data processor for executing various processes with utilizing map data stored in a memory medium obtains new map data from an external system via a communication system. Based on the new map data, a map database stored in the memory medium is up-dated. Here, the map data processor is, for example, a navigation device. When a new road and/or a new facility are constructed, the map data processor obtains information about the new road and the new facility in each case so that the map database is up-dated with utilizing the information. Thus, the convenience of the map data processor is improved.
The map data processor is disclosed in, for example, JP-A-2003-315054. A navigation device in JP-A-2003-315054 receives a part of new version map data, which is divided in each predetermined region, from an external data center, so that a database in the processor is up-dated in each region.
Further, when the map data is up-dated, the processor obtains a part of new data for up-dating, which is divided in each link, from the external system. Here, the link is a minimum unit of road regions, and the part of the new data in each link is defined as a new link data. Based on the new link data, the map database is up-dated.
Thus, the new link data obtained from the external system is added to the map database stored in the memory medium. When the map database is utilized, it is necessary to connect the new link with a road network defined in the map database. In this case, it is necessary to specify a link ID as an identification information of an existing link to be connected with the new link so that the new link is incorporated in the existing road network. However, the link ID defining the existing link in the database is available for the present map database, to which the link belongs. Thus, the link ID lacks generality. Accordingly, a provider for providing a new link data to a user has to obtain a specific link ID of the map database of the user. Unless, it is difficult to specify the link ID for obtaining connection relationship between the new link and the existing link. Thus, the provider cannot incorporate the new link into the map network of the user if the provider does not know the information about the connection relationship. Thus, it is inconvenient for both of the provider and the user to utilize the new link ID.